1. Field of the Invention
This invention relates to a device and process for cleaning, shelling, and sizing nuts in one step. The invention eliminates hand shelling of pods by separating out the unshelled nuts from shelled kernels based on density using vertical air column separators. The invention is modular in size and design so that it can fit in existing grading rooms to replace current cleaners, pre-sizers, shellers, and kernel sizers.
2. Description of the Prior Art
The peanut industry has identified an immediate need to improve sampling, grading, and marketing of peanuts. The United States peanuts are considered to be the highest quality of peanuts available worldwide. To continue to be the world leader, one of the areas for improvement includes the grading of farmers stock peanuts especially for removal of foreign material from the stock (U.S. Peanut Quality: An Industry Commitment. 1988--A Consensus Report of the Peanut Quality Task Force, National Peanut Council, Alexandria, Va. December, 1987). Farmers stock peanuts are picked or threshed peanuts which have not been shelled or otherwise altered and usually contain foreign material. Foreign material is everything other than peanuts in the shell found in farmers stock. This includes dirt, hay, sticks, dirt clods, stones, insects, broken shells, pieces of glass, soybeans, corn kernels, loose shelled kernels (LSKs), and "raisins or twisters". "Raisins or twisters" are extremely immature, undeveloped peanuts with badly shriveled and shrunken shells. Loose shelled kernels (LSKs) are completely free from hulls and are scattered in farmers stock. These are undesirable since kernels generally maintain quality better if they are inside of good sound hulls.
There are about 500 peanut grading rooms throughout the United States which grade about 600,000 samples of peanuts each year using a peanut grading system which has been in place since the 1960's and is judged as inaccurate, slow, and labor intensive by the National Peanut Council, the Federal State Inspection Service, the Peanut Grading Working Group, the Peanut Administration Committee, and the Southeastern Peanut Association. The system requires the almost constant attention of at least two inspectors per grading room to assist the cleaning, pod pre-sizing, shelling, and kernel sizing machines as well as to transfer the samples from one machine to the next. Furthermore, the machines used for cleaning and shelling are not complete in their operation and require inspectors to hand clean and shell portions of each sample. The entire current process from cleaning through kernel sizing requires about 20 minutes.
Devices which combine shelling and/or grading steps for nuts have been developed. The prior art machines of Dragon (U.S. Pat. No. 2,220,320), Vaughan (U.S. Pat. No. 1,564,914), Branda (U.S. Pat. No. 1,869,658), Hill (U.S. Pat. No. 328,032), McGehee (U.S. Pat. No. 3,951,056) and Bailey (U.S. Pat. No. 1,975,761) do not remove foreign material or LSKs from the stock prior to the shelling step. The machine of Nehrhood (U.S. Pat. No. 1,576,244) removes small foreign material using a mesh screen (15) but does not remove large foreign material or LSKs before shelling.
Another step prior to shelling is pre-sizing which separates the in-shell peanuts according to size making it possible for the sheller to operate more efficiently. Nehrhood ('244) and Bailey ('761) both have pre-sizing apparatus on their devices. Nehrhood's apparatus pre-sizes using a revolving drum (14) made up of screens of different mesh which can be changed to suit the size or character of the nuts being shelled. However, with indeterminate crops such as peanuts, unshelled pods may be the same diameter as large shelled kernels and the two would not be separated. Furthermore, the nuts will not be sized based on their maximum diameter since they may not orient themselves in a manner that allows them to fall through the perforated screens. The machine of Bailey ('761) uses rollers to pre-size the unshelled nuts which are then passed on to the sheller. However, the sheller also receives any LSKs and other foreign materials.
The final step after shelling is sizing of the shelled kernels. The machines of Branda ('658), Nehrhood ('244), and Hill ('032) all have mechanisms which size the shelled kernels using perforated screens which are not precise since the nuts are not always sized by their maximum diameter.
While various devices have been developed for combining the steps of processing unshelled nuts, there still remains a need in the art for a more effective device for shelling and grading nuts.